AC issues

[Bigbertha78]

i have a 2004 Tahoe Z71 with 135,000 miles and the manual slide AC/heat controls. I have the AC on and everything blows out normal driving down the road but then the out put from the vents gets slower, like I were to turn the setting down but I haven't touched anything. When I turn it down to say #1 setting it barely blows out any AC at all. Any thoughts? Other issue is driving it is cold but when it comes to a stop for any amount of time it slowly starts to get warmer, any thought? I was thinking either the Freon was low or there is an issue with the blower resistor. The rear AC blows out air but is not cold. Figured I would post here since there was no response on interior.

 

[ivin74]

Try changing out the ac blower fan resistor, that might fix your issue

 

[ccapehartusarmyINF.(ret)]

at stops when it starts blowing warmer air hows yer enngine temp my tahoes AC quit workin whenever i was stopped and idling but the engine temp started to creep up over 210
the fan clutch went out on mine then throw in the 110 plus tempurature here in phoenix

 

[Bigbertha78]

Never really paid much attention, but I will check in the morning and report back. Thanks

 

[Bigbertha78]

So the coolant temp never hits 210 but it stay's right under, once we start driving it cools down just a hair. I know it's a little warm but at 114 degrees outside, it is expected. I'll try the blower resistor for the fan speed but as far as the cool air, I'll have to try the little can of refrigerant to see if it helps.

 

[Bigbertha78]

So after pulling the blower resistor out, the part number is not matching anything that I have found!it has a cover that fits over the two hole unit to make it a 4 hole. Any ideas on the OE number that is comparable to the P/N 15305077? Did a search on the part and it is discontinued per the GM site. Any help would be awesome.

 

[Bigbertha78]

Update* Went to Walmart and picked up a can of the R134a refrigerant to see if I could recharge the system and get it to blow a little colder. Turned truck on turned on front AC full blast and hooked up the pressure hose and the reading was 85psi first time, 100psi second time. Compressor was on and AC inside truck was cooling, any ideas what could be wrong. I never replaced the Blower Resistor, could that have any effect on the high pressures either?

 

[mizzouguy]

Mine does the same thing pressure wise. High low side and low high side pressures normally indicates a weak compressor, or so I thought. Mine acts the same was as yours; at a stop blowing warmer etc. I checked my fan clutch and it was good. I ended up changing out the orifice tube and drier, pulling a vacuum, and refilling by weight with a professional machine to get the exact correct amount r134. Still blew a little warm at a stop so i added an auxiliary pusher fan in front of the condenser to try to simulate better airflow like when moving. Helped a little and that was last summer and still no change in performance from then to now.

 

[Bigbertha78]

Went out for another drive thinking it was just over pressurized, came back home and re-checked the low side pressure again and it was at 55psi this time which is right at the top of good. Maybe since the temps are so hot here outside it just gets a little warmer. I have no idea, going to take it to Firestone tomorrow and have them hook up high and low side to see if there is something.

Update to the Blower Resistor; went to Autozone and looked up by part number of old resistor and the autozone part would not fit. Anyone have ideas on which part # for replacement?

 

[mizzouguy]

Most aftermarket replacements have been redesigned. I believe even the gm part number is the new style. Supposed to help with them failing so often. You have to cut a plug off and connect it to a new plug that is supplied. All the wire colors are the same. I know for a fact it is this way with BWD and the auto one. Make sure they ask if you have auto climate control or manual, and the number of mounting holes. BWD RU1064 is two hole mounting manual controls, BWD RU1264 is 4 hole mounting manual controls. They should both come with and use PT5793 connector.